TO GEOLOGY. 133 



shell thin ; spire elevated and acute at apex ; whorls ten, 

 with an elevated band below the suture; mouth rather 

 narrow, about one third the length of the shell. 



Length .5, Breadth .2, of an inch. 



Observations. A pretty little species, and may be distin- 

 guished by its elevated spire, and the band which surrounds 

 the whorls below the suture. 



P. Sayi* Plate 4. Fig. 125. 



Description. Shell fusiform, turrited, longitudinally and 

 thickly folded, transversely and strongly striate ; substance 

 of the shell rather thin ; spire elevated, pointed at the apex ; 

 whorls eight, subcanaliculate above; mouth rather narrow, 

 about one third the length of the shell. 



Length .5, Breadth .2, of an inch. 



Observations. This species very closely resembles the 

 last described, but may be distinguished by its more 

 numerous folds and stronger striae, which are disposed to 

 be larger and smaller alternately. It has a strong resem- 

 blance to the _species figured by Sowerby under the name 

 of P. comma, f 



P. monilifera. Plate 4. Fig. 126. 



Description. Shell fusiform, turrited, transversely stri- 

 ate, furnished with a larger and smaller row of tuber- 



* Named after the distinguished naturalist Thomas Say. 

 t Min. Conch, plate 146, fig. 5. 



